The Liberating Potential of Essentrics - Embracing Stretch and Strength
When we move our bodies, we have two different kinds of contractions: concentric contractions (shortening) and eccentric contractions (stretching). Both are vital in life and used in Essentrics; however, the focus in Essentics is more on the eccentric (stretching) contraction. By looking deeper within the body, we can discover more about what is involved in both the concentric and eccentric contractions. Our muscle muscles are composed of parallel muscle fibers, known as bundles, and these bundles are composed of smaller structures called myofibrils. Within these myofibrils are contractile units known as sarcomeres. As they operate, they use what is called "filament theory" or "sliding filament theory." This theory has a crucial role in movement and health.
The filament theory explains that muscle contraction (both concentric and eccentric) occurs as a result of the sliding action between myosin (thick filament) and actin (thin filament), leading to the shortening or lengthening of the sarcomere. During eccentric movement, the sarcomere lengthens, and the muscle fiber experiences approximately 75% extra stretching beyond its original (best resting) length. You can think of eccentric movement like a hypodermic, drawing more oxygen-filled blood into the muscle. This oxygen-filled blood plays a vital role in muscle function and overall flexibility, as well as promoting healing. In contrast, in a concentric contraction, the muscle fiber experiences approximately 25% shortening beyond its original (best resting) length. The concentric contracting muscles compress nearby blood vessels. This action helps to efficiently facilitate deoxygenated blood to pump back to the heart and lungs for oxygenation. Also, it assists in the movement of lymph, the colorless fluid containing white blood cells that bathes the tissues and drains through the lymphatic system into the bloodstream. Lymph plays a vital role in the body's immune system by transporting infection-fighting cells throughout the body, thus contributing to the body's overall circulatory and immune system function.
This concentric contraction is generally accepted as the primary explanation for how muscles generate force and produce movement within the rank-and-file fitness and wellness community. Think of grunting, groaning, and bulking up.
In counterpoint, Essentrics, in its holistic approach to muscle health, underscores the significance of muscle lengthening and strengthening. It also leverages the body's natural reflex, the Myotatic Reflex, when the body is in stretch mode, further enhancing the exercise's effectiveness. Think of taking a deep breath, yawning, and becoming longer and leaner.
This myotatic reflex, also known as the stretch reflex, is a protective mechanism that occurs when your muscle has stretched. It involves a reflexive contraction of the muscle in response to its lengthening. When a muscle stretches to its most prolonged, sensory receptors called muscle spindles within the muscle are activated, sending signals to the spinal cord. In response, motor neurons activate, leading to a reflexive contraction of the muscle to prevent overstretching and protect against potential injury.
In Essentrics, we not only understand the myotatic reflex but also use it to our advantage. When you stretch a muscle, the myotatic reflex initially causes the muscle to resist the stretch. However, as you hold the stretch, the reflex gradually diminishes, allowing you to find a slight bit more stretch (Essentrics calls this "Going to the end of your stretch") for more significant muscle lengthening. This process, when repeated over time, can significantly improve flexibility and range of motion. By gradually stretching and holding a position and deepening into that stretch, you can encourage the muscles to relax and lengthen, taking full advantage of the body's natural adaptive mechanisms. Understanding the Myotactic Reflex in relation to eccentric stretching can be a powerful tool in your journey to improved flexibility and mobility.
Essentrics embodies the profound impact of understanding and applying the filament theory and our natural reflexes in optimizing movement and overall physical well-being.
About this Image: Tensile Involvement, choreographed by Alwin Nikolais circa 1955
Nik uses long pieces of elastic that make the stage shimmer as the dancers manipulate the elastic in ingenious ways, creating various kinetic landscapes. I thought of this image as the costumes remind me a bit of myofibrils. I also had the pleasure of dancing Tensile Involvement so many times during my time touring with the company.
Here is a link if your interested in seeing about a minute of Tensile Involvement performed by Ririe-Woodbury Dance in 2012 YouTube - Tensile Involvement - Ririe-Woodbury Dance 2012 - 1:18
